“They’re engineered to make a 3,000-mile trip, so they look good but taste like a piece of wood,” said Shawn Baldwin, Wal-Mart Stores Inc.’s senior vice president for produce and global food sourcing. “So we said, ‘Wouldn’t it be nice to have that summer melon taste in the fall?’”

Wal-Mart says it typically sells 10 times more cantaloupes in June, when it can buy from U.S. farms, than it does in December, when the melons are grown farther south. Most retailers don’t have the mojo to do anything about it.

But Wal-Mart is the biggest U.S. grocer. If it wants to sell a cantaloupe off-season that tastes as sweet and juicy as in summer — and keeps it a step ahead of discount competitors nipping at its heels — it gets to.

The retailer teamed up with seed experts at German agriculture giant Bayer AG to help develop a bespoke melon that’s pleasing to the palate but still tough enough for the trek from warmer climes.

Wal-Mart considered more than 100 varieties of seeds and tested 20. Wal-Mart employees spent six months grading the cantaloupes on attributes like flavor, texture and aroma.

The winner was dubbed the Sweet Spark, after the yellow sunburst in Wal-Mart’s logo. The designer cantaloupes are available in 200 U.S. stores with a full roll-out planned for fall. Sweet Spark is not genetically modified.

“I hate the name but that’s what the employees picked,” said Baldwin, who preferred Winter Wonder. The new cantaloupe is as much as 40 per cent sweeter than Wal-Mart’s current winter melons, according to the so-called Brix scale, which measures sugar content.

It’s “very rare” for a retailer to invest in the exclusive development of a new variety of fruit, according to Rabobank International produce analyst Roland Fumasi, though growers often cultivate new breeds and offer them to a retailer for a short period.

For now, Wal-Mart has exclusive rights to sell Sweet Spark. The company will try to negotiate a long-term arrangement with Bayer. If that falls through, it’s possible the cantaloupe variety could be sold at rival retailers.

Boosting Produce

Sweet Spark is part of a push by Chief Executive Officer Doug McMillon to boost Wal-Mart’s produce department, which is the first thing shoppers see when they enter the store. Customers who buy fruits and vegetables spend 55 per cent more on their trips, according to data tracker Nielsen.

Wal-Mart is doing all it can to keep grocery rivals at bay. For now, at least, a juicy ripe cantaloupe in the dead of U.S. winter isn’t something easily delivered by Amazon.com Inc. The world’s biggest internet retailer is pushing into the grocery business and chasing Wal-Mart’s lower-income shoppers. But it can’t match its global food supply chain.

Produce is a key weapon in Wal-Mart’s battle against Europe-based deep-discount chains Aldi and Lidl, which have expanded into the U.S. with prices on packaged foods, like soup and cereal, that often beat Wal-Mart’s.

Up next: tomatoes. Wal-Mart’s Baldwin said he wants to replicate the blend of sweetness and acidity in the San Marzano variety of Naples, Italy.

“When you’re as big as Wal-Mart, you can dictate a lot of what you want to see in produce,” said Kent Bradford, a professor and director of the Seed Biotechnology Center at the University of California at Davis.